Nola Murphy's 73rd birthday was almost her last when she was served a toxic cleaning chemical in a soft-drink bottle instead of the lemonade she had ordered at an Auckland RSA club.

The mistake has prompted a nationwide review of RSA cleaning and bar procedures.

Mrs Murphy was taken to hospital after drinking the fluid at the Avondale Returned and Services Association on February 23.

She went to the club for a birthday drink with her friend Heatha Anderson and ordered her "usual", a Sprite Zero lemonade.

"I picked up the drink and drank it as normal. Suddenly, my head just exploded, everything just exploded," she said yesterday.

"All I could think of was getting to the toilet and throwing up. But I couldn't breathe.

"It had blocked my whole airway off. I couldn't yell for help, I couldn't say what was happening.

My legs were buckling underneath me, I was gasping for breath.

"I didn't know what was happening. My mind was just on getting that breath. I could not breathe. My eyes were popping out. I could feel them. It was pouring out of my nose and I was just holding on to the edge of the sink thinking, 'Get that breath, get that breath'."

The bottle held a surface cleaner containing the lethal chemical benzalkonium chloride.

About five weeks before the incident, a cleaner at the RSA had filled the Sprite bottle with the fluid and placed it on the bar.

She then worked on another area and forgot to put the bottle back in the cleaning cupboard.

Another staff member put the bottle in the refrigerator with the other soft drinks.

It was later served to Mrs Murphy.

After Mrs Murphy became unwell, Mrs Anderson took a sip from the glass to see if the drink had caused the reaction.

"I tested it and it burned my mouth straight away. I spat it out, but it still burned," she said. "Then I started throwing up."

Both women were taken to Auckland City Hospital.

They reported the incident to the police, who took the bottle - which Mrs Anderson had kept - for testing.

RSA national chief executive Stephen Clarke said the incident was "very unfortunate".

"It was a terrible mistake. It was a number of mistakes by a number of people."

Dr Clarke said the cleaner had offered to resign. "She is devastated. She's been a long-serving member, and has an unblemished record."

She is to meet management to discuss her future.

Dr Clarke said the incident had also prompted a review of practices at all RSAs.

"The Avondale club is working with police. Police see it as a terrible mistake and have said to Avondale, 'Use this as training'. And they are. They are changing all their health and safety [protocols] around cleaning materials."

Mrs Murphy said she was feeling better but "my doctor said my throat was a bloody mess".

"Every now and then I wake up in the middle of the night and I think, 'Where's my breath'. It's scary. I nearly lost my bloody life.

"I was wild. I've never been so angry in my life. There is no way they should be doing that - storing cleaning stuff in drink bottles. I was disgusted. I just cannot believe it happened."

Dr Michael Beasley, a medical toxicologist at the National Poisons Centre in Dunedin, said benzalkonium chloride was toxic and ingestion had led to at least one death.